A patient controlled analgesia (PCA) oral narcotic dispenser has been designed by the Anesthesia Section and Bioengineering Section of the Clinical Center. This device will be used for evaluating post operative pain control in the post cardiac surgical patient. Intravenous PCA has been used at the Clinical Center and several criticisms of this mode of administration have been addressed with the oral machine design. Twenty patients will be allowed to use the equipment. The medication used will be percocet. The efficacy of this mode of administration and its comparison with other standard modes will be examined.